[en] Planktonic and benthic incubations (bare and Posidonia oceanica vegetated sediments) were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the Bay of Palma (Mallorca, Spain). Results showed a contrast between the planktonic compartment, which was on average near metabolic balance (-4.6 +/- 5.9 mmol O-2 m(-2) d(-1)) and the benthic compartment, which was autotrophic (17.6 +/- 8.5 mmol O-2 m(-2) d(-1)). During two cruises in March and June 2002, planktonic and benthic incubations were performed at several stations in the bay to estimate the whole-system metabolism and to examine its relationship with partial pressure of CO2 (pCO(2)) and apparent oxygen utilisation (AOU) spatial patterns. Moreover, during the second cruise, when the residence time of water was long enough, net ecosystem production (NEP) estimates based on incubations were compared, over the Posidonia oceanica meadow, to rates derived from dissolved inorganic carbon (DIC) and oxygen (O-2) mass balance budgets. These budgets provided NEP estimates in fair agreement with those derived from direct metabolic estimates based on incubated samples over the Posidonia oceanica meadow. Whereas the seagrass community was autotrophic, the excess organic carbon production therein could only balance the planktonic heterotrophy in shallow waters relative to the maximum depth of the bay ( 55 m). This generated a horizontal gradient from autotrophic or balanced communities in the shallow seagrass-covered areas, to strongly heterotrophic communities in deeper areas of the bay. It seems therefore that, on an annual scale in the whole bay, the organic matter production by the Posidonia oceanica may not be sufficient to fully compensate the heterotrophy of the planktonic compartment, which may require external organic carbon inputs, most likely from land.
DG RDT - Commission Européenne. Direction Générale de la Recherche et de l'Innovation CNRS - Centre National de la Recherche Scientifique CGRI - Commissariat général aux Relations internationales F.R.S.-FNRS - Fonds de la Recherche Scientifique
Allen, J. T., Alderson, S. G., Ruiz, S., Nurser, A. G., and Griffiths, G.: Shipboard VM-ADCP observations during RRS Discovery cruise 224, Internal Document n°21, Southampton Oceanography Centre, 1997.
Atkinson, M. J. and Smith, S. V.: C:N:P ratios of benthic marine plants, Limn. Ocean., 28 (2), 568-574, 1983.
Barranguet, C., Herman, P. M. J., and Sinke, J. J.: Microphytobenthos biomass and community composition studied by pigment bimoarkers: importance and fate in the carbon cycle of a tidal flat, J. Sea Res., 38, 59-70, 1997.
Bégovic, M. and Copin-Montégut, C.: Processes controlling annual variations in the partial pressure of CO2 in surface waters of the central northwestern Mediterranean Sea (Dyfamed site), Deep-Sea II, 49 (11), 2031-2047, 2002.
Benson, B. B. and Krause, D. J.: The concentration and isotopic fractionation of oxygen dissolved in fresh water and seawater in equilibrium with the atmosphere, Limn. Ocean., 29 (2), 620-632, 1984.
Bethoux, J. P. and Copin-Montégut, G.: Biological fixation of atmospheric nitrogen in the Mediterranean Sea, Limn. Ocean., 31 (6), 1353-1358, 1986.
Borges, A. V. and Frankignoulle, M.: Short-term variations of the partial pressure of CO2 in surface waters of the Galician up-welling system, Prog. Ocean., 51 (2-4), 283-302, 2001.
Borges, A. V. and Frankignoulle, M.: Distribution of surface carbon dioxide and air-sea exchange in the upwelling system off the Galician coast, Global Biogeochem., 16 (2), art. no. 1020, doi:10.1029/20000GB001385, 2002.
Borges, A. V., Delille, B., Schiettecatte, L.-S., Gazeau, F., Abril, G., and Frankignoulle, M.: Gas transfer velocities of CO2 in three European estuaries (Randers Fjord, Scheldt and Thames), Limn. Ocean., 49(5), 1630-1641, 2004.
Carrit, D. E. and Carpenter, J. H.: Comparison and evaluation of currently employed modifications of the Winkler method for determining dissolved oxygen in seawater: a NASCO Report, J. Marine Res., 24, 286-319, 1966.
Chen, C. T. A., Liu, K. K., and Macdonald, R.: Continental margin exchanges, in: Ocean biogeochemistry, edited by: Fasham, M. J. R., Springer, 53-97, 2003.
Copin-Montégut, C.: A new formula for the effect of temperature on the partial pressure of CO2 in seawater, Mar. Chem., 25, 29-37, 1988.
Copin-Montégut, C.: A new formula for the effect of temperature on the partial pressure of carbon dioxide in seawater, Corrigendum, Mar. Chem., 27, 143-144, 1989.
Copin-Montégut, C.: Alkalinity and carbon budgets in the Mediterranean sea, Global Biogeochem., 7 (3), 915-925, 1993.
Dickson, A. G.: Thermodynamics of the dissociation of boric acid in synthetic seawater from 273.15 to 318.15 K, Deep-Sea A, 375 (4), 755-766, 1990.
Dickson, A. G.: pH buffers for sea water media based on the total hydrogen ion concentration scale, Deep-Sea I, 40 (1), 107-118, 1993.
Duarte, C. M. and Cebrián, J.: The fate of marine autotrophic production, Limn. Ocean., 41 (8), 1758-1766, 1996.
Duarte, C. M. and Agustí, S.: The CO2 balance of unproductive aquatic ecosystems, Science, 281 (5374), 234-236, 1998.
Duarte, C. M. and Chiscano, C. L.: Seagrass biomass and production: a reassessment, Aqua Bot., 65, 159-174, 1999.
Duarte, C. M. and Prairie, Y. T.: Prevalence of heterotrophy in aquatic systems, Ecosystems, in press, 2005.
Duarte, C. M., Agustí, S., Kennedy, H., and Vaqué, D.: The Mediterranean climate as a template for Mediterranean marine ecosystems: the example of the northeast Spanish littoral, Prog. Ocean., 44 (1-3), 245-270, 1999.
Frankignoulle, M.: Field measurements of air-sea CO2 exchange, Limn. Ocean., 33 (2), 313-322, 1988.
Frankignoulle, M., Borges, A., and Biondo, R.: A new design of equilibrator to monitor carbon dioxide in highly dynamic and turbid environments, Water Res., 35 (4), 1344-1347, 2001.
Frankignoulle, M., Gattuso, J.-P., Biondo, R., Bourge, I., Copin-Montégut, G., and Pichon, M.: Carbon fluxes in coral reefs. 2. Eulerian study of inorganic carbon dynamics and measurement of air-sea CO 2 exchanges, Mar. Ecol.-Pr, 145 (1-3), 123-132, 1996.
Gattuso, J.-P., Frankignoulle, M., and Wollast, R.: Carbon and carbonate metabolism in coastal aquatic ecosystems, Ann. R. Ecol., 29, 405-434, 1998.
Gordon, D. C. J., Boudreau, P. R., Mann, K. H., Ong, J.-E., Silvert, W. L., Smith, S. V., Wattayakorn, G., Wulff, F., and Yanagi, T.: LOICZ biogeochemical modelling guidelines, LOICZ Reports & Studies, 5, 1-96, 1996.
Griffiths, G.: Using 3DF Ashtech GPS heading for improving underway ADCP data, J. Atmos. Oc., 11, 1135-1143, 1994.
Hansen, H. P. and Koroleff, F.: Determination of nutrients, in: Methods of seawater analysis, edited by: Grasshoff, K. Kremling, K., and Ehrhardt, M., Weinheim, Wiley-VCH Verlag, 159-226, 1999.
Hansen, J. W., Thamdrup, B., and Jørgensen, B. B.: Anoxic incubation of sediment in gas-tight plastic bags: a method for biogeochemical process studies, Mar. Ecol.-Pr, 208, 273-282, 2000.
Hedges, J. I., Baldock, J. A., Gelinas, Y., Lee, C., Peterson, M. L., and Wakeham, S. G.: The biochemical and elemental compositions of marine plankton: a NMR perspective, Mar. Chem., 78 (1), 47-63, 2002.
Hemminga, M. A. and Duarte, C. M.: Seagrass Ecology, Cambridge University Press, Cambridge, 2000.
Holmer, M., Duarte, C. M., and Marbá, N.: Sulfur cycling and sea-grass (Posidonia oceanica) status in carbonate sediments, Biogeochem., 66, 223-239, 2003.
Hopkinson, C. S. J. and Smith, E. M.: Estuarine respiration: an overview of benthic, pelagic and whole system respiration, in: Respiration in aquatic ecosystems, edited by: del Giorgio, P. A. and Williams, L. P. J., Oxford, Oxford University Press, 123-147, 2005.
Jansà, J., Lopez-Jurado, J. L., Amengual, R., Reñones, O., and Morillas, I.: Variación anual e interanual de los factores fisicoquímico-biológicos generales del medio pelágico de la Bahia de Palma (Islas Baleares, España) desde Mayo de 1988 hasta Mayo de 1992, Informes técnicos, Instituto Español de Oceanografía, 152, 1994.
Knap, A. H., Michaels, A. E., Close, A., Ducklow, H. W., and Dickson, A. G. (Eds.): Protocols for the Joint Global Ocean Flux Study (JGOFS) core measurements, JGOFS Report No. 19, Bergen, Norway, Unesco, 1996.
Liss, P. S. and Merlivat, L.: Air-sea gas exchange rates: introduction and synthesis, in: The role of air-sea exchange in geochemical cycling, edited by: Buat-Menard, P., Dordrecht, D. Reidel Publishing Company, 113-127, 1986.
Liu, K. K., Iseki, K., and Chao, S. Y.: Continental margin carbon fluxes, in: The changing ocean carbon cycle: a midterm synthesis of the Joint Global Ocean Flus Study, edited by: Hanson, R. B., Ducklow, H. W., and Field, J. G., Cambridge University Press, 187-239, 2000.
McGillis, W. R., Edson, J. B., Ware, J. D., Dacey, J. W. H., Hare, J. E., Fairall, C. W., and Wanninkhof, R.: Carbon dioxide flux techniques performed during GasEx-98, Mar. Chem., 75, 267-280, 2001.
Navarro, N., Agustí, S., and Duarte, C. M.: Plankton metabolism and DOC use in the Bay of Palma, NW Mediterranean Sea, Aquat. Mic. E., 37, 47-54, 2004.
Nightingale, P. D., Malin, G., Law, C. S., Watson, A. J., Liss, P. S., Liddicoat, M. I., Boutin, J., and Upstill-Goddard, R. C.: In situ evaluation of air-sea gas exchange parameterizations using novel conservative and volatile tracers, Global Biogeochem., 14 (1), 373-387, 2000.
Odum, H. T.: Primary production in flowing waters, Limn. Ocean., 1 (2), 102-117, 1956.
Oudot, C., Gerard, R., Morin, P., and Gningue, I.: Precise shipboard determination of dissolved oxygen (Winkler procedure) for productivity studies with a commercial system, Limn. Ocean., 33 (1), 146-150, 1988.
Pedder, M. A.: Interpolation and filtering of spatial observations using successive corrections and Gaussian filters, Monthly Weather Review, 121, 2889-2902, 1993.
Platt, T., Gallegos, C. L., and Harrison, W. G.: Photoinhibition of photosynthesis in natural assemblages of marine phytoplankton, J. Marine Res., 38, 687-701, 1980.
Ramis, C., Jansá, A., and Alonso, S.: Sea breeze in Mallorca, A numerical study, Meteor. Atm., 42, 249-258, 1990.
Redfield, A. C., Ketchum, B. H., and Richards, F. A.: The influence of organisms on the composition of sea-water, in: The sea, edited by: Hill, M. N., New York, Wiley, 2, 26-77, 1963.
Rey, J. and Diaz del Rio, V.: Cartographia de los fondos marinos de la bahia de Palma (Baleares, España): distribution de las praderas vegetales y sedimentos superficiales, International Workshop on Posidonia Oceanica Beds, Porquerolles, 1984.
Roy, R. N., Roy, L. N., Vogel, K. M., Porter-Moore, C., Pearson, T., Good, C. E., Millero, F. J., and Campbell, D. M.: The dissociation constants of carbonic acid in seawater at salinities 5 to 45 and temperatures 0 to 45°C, Mar. Chem., 44 (2-4), 249-267, 1993.
Smith, S. V. and Hollibaugh, J. T.: Coastal metabolism and the oceanic organic carbon balance, Rev. Geophys., 31 (1), 75-89, 1993.
Thamdrup, B. and Canfield, D. E.: Benthic respiration in aquatic sediments, in: Methods in ecosystem science, edited by: Sala, O. E., Jackson, R. B., Mooney, H. A., and Howarth, R. W., New York, Springer, 86-103, 2000.
Wanninkhof, R.: Relationship between wind speed and gas exchange over the ocean, J. Geophys. Res., 97 (C5), 7373-7382, 1992.
Wanninkhof, R. and McGillis, W. R.: A cubic relationship between air-sea CO2 exchange and wind speed, Geophys. Res. Lett., 26 (13), 1889-1892, 1999.
Weiss, R. F.: Carbon dioxide in water and seawater: the solubility of a non-ideal gas, Mar. Chem., 2, 203-215, 1974.
Wollast, R.: Evaluation and comparison of the global carbon cycle in the coastal zone and in the open ocean, in: The Sea, edited by: Brink, K. H. and Robinson, A. R., New York, John Wiley & Sons, 10, 213-252, 1998.
